Indirect lamps of this type, the design of which solves the problem of excessive brightness on the ceiling directly above the lamp in spite of a short distance between the ceiling of the room and the lower edge of the lamp while at the same time allowing most of the light to be directed laterally and obliquely upward to achieve good, uniform illumination of the room, are known from DE-C1 195-37,685.
Whereas this indirect lamp effectively solves the problem described above for fluorescent tubes with a diameter of 26 mm and a corresponding brightness, the problem becomes so much worse when fluorescent tubes with a diameter of 16 mm are used that the known lamp is no longer adequate in all cases.